In many types of pressurized water reactors (PWR) and boiling water reactors (BWR), a reactor core may contain a large number of fuel rods that are several meters in height. The reactor core may be surrounded by water contained within a reactor vessel. Additionally, the reactor may contain one or more control rod drive mechanism (CRDM) assemblies including a number of control rod assemblies that may be inserted into, and withdrawn from, the reactor core to control the overall power level of the reactor.
The CRDM assembly may include a number of magnetic coils operable to raise and lower the control rod assemblies. For example, the magnetic coils may be used to move the control rod assemblies out of the reactor core in incremental steps. Many CRDM assemblies are designed such that a loss of electrical power will result in the magnetic coils automatically releasing the control rod assemblies into the reactor core, in what is referred to as a reactor trip or scram.
The CRDM assembly may additionally comprise sensing coils aligned along a direction of motion of a control rod which, when actuated, may pass through the center of the sensing coils as the control rod is moved. In known CRDM assemblies, the sensing coils may be associated with a control rod position indicator (RPI) assembly. The RPI assembly may comprise numerous sensing coils. Each sensing coil may comprise or be associated with two terminals. In an example for an RPI assembly that includes 78 sensing coils, there may be 156 terminals and/or 156 wires associated with each of the control rods. Additionally the CRDM assembly may be associated with dozens of control rods, which has the effect of similarly multiplying the total number of wires in the RPI assembly.
Some known RPI assemblies may be located within a containment structure that houses the reactor vessel. The wires associated with the RPI assembly may have one end attached at or near the top of the reactor vessel, and another end that passes through the containment structure to transmit the information to an external processing device and/or monitor. A number of penetrations through the containment structure may therefore be associated with the multitude of wires of the RPI assembly.
Additionally, known RPI assemblies may comprise or be associated with two separate power supplies. Each of the power supplies may be configured to supply voltage to half of the sensing coils. Utilizing two power supplies may be configured to allow the sensing coils to continue operating at lower resolution if one of the power supplies is shut off or otherwise becomes inoperable.
Some RPI assemblies may utilize a dual common bus power supply. Each of the sensing coils corresponding to the dual common bus power supply may have one of its two corresponding terminations connected to the bus. The other termination may be separately fed out of the containment structure for processing. Although the number of terminations passing through the containment structure may be approximately half as many as compared to RPI assemblies associated with two power supplies, there may still be 78 or more wires that need to pass through the containment structure for the example RPI assembly provided above, having 78 sensing coils.
Accordingly, the large number of wires associated with known RPI assemblies creates a significant challenge to maintain a sealed containment structure due to the number and/or size of the penetrations that are required to pass the wires through the containment structure. Additionally, the large number of wires causes significant complexity and a corresponding amount of time to label, connect, disconnect, route, or otherwise handle the wires during manufacture, installation, maintenance, operation, and/or decommissioning of the reactor module.
This application addresses these and other problems.